PSI - Issue 67

Dan Huang et al. / Procedia Structural Integrity 67 (2025) 61–79 Huang, D., Velay-Lizancos, M., Olek, J./ Structural Integrity Procedia 00 (2024) 000–000

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1. Introduction In a region with a cold climate, transportation infrastructure constructed from concrete (including pavement, bridges, sidewalks, etc.) may suffer adverse effects due to freeze-thaw cycles (Harnik et al., 1980; Mehta & Monteiro, 2001; J. J. Valenza & Scherer, 2005). Especially in the late fall and winter season, such low temperature during the placement of concrete in the field leads to a challenging curing environment for concrete. Concrete placed at low temperature is typically more sensitive to failure (Husem & Gozutok, 2005; Kim et al., 1998). Furthermore, freeze-thaw cycles, coupled with the presence of deicing chemicals, can lead to damage such as surface scaling (John J. Valenza & Scherer, 2007a, 2007b). This type of damage is often observed on flat surfaces such as pavements and bridge decks, manifesting as the gradual removal of small flakes or chips of the material. (John J. Valenza & Scherer, 2007a). Besides being aesthetically unpleasing, neglected damage of this nature can degrade ride quality and expose the underlying layers of concrete, microstructure, thereby increasing the risk of future deterioration from freeze-thaw cycles by facilitating the penetration of chloride ions and moisture (Verbeck & Klieger, 1957; Wu et al., 2014). It has been reported previously that numerous instances of scaling damage in real-world scenarios have been linked to factors such as poor mix design, subpar finishing, and inadequate curing (Afrani & Rogers, 1994; Amini et al., 2019; Panesar & Chidiac, 2007). However, there remains room for enhancing the inherent durability of concrete through the application of nanoparticles. The utilization of nanoparticles has garnered significant interest from both industry and research communities because of their unique physical and chemical attributes, such as extremely small particle size and high specific surface area (Z. Li et al., 2018; Ren et al., 2018; Shekari & Razzaghi, 2011). It was reported that adding a relatively small amount of nano-TiO 2 in concrete mixtures accelerates the hydration process (Chen et al., 2012; D Huang et al., n.d.; Jayapalan et al., 2009), enhances the mechanical properties(D Huang et al., n.d.; Dan Huang et al., n.d.; Jalal et al., 2013), and improves the durability of concrete (Dan Huang et al., n.d., 2023; Ma et al., 2015; Zhang & Li, 2011), especially when curing temperature is low (Francioso et al., 2019; D Huang et al., n.d.). Such an improvement in the properties of cementitious composites is mainly due to the nucleation effect of nano-TiO 2 , which provides more nucleation sites and facilitates the hydration process of cementitious materials (Chen et al., 2012; Z. Li et al., 2018). Moreover, the incorporation of nanoparticles into cementitious composites induces a pore-filling effect, resulting in an improved particle packing density (Z. Li et al., 2018). Such an improved particle packing density, therefore, leads to an enhanced compressive strength of concrete (Abd Elrahman & Hillemeier, 2014; L. G. Li et al., 2017; Sun et al., 2018). Furthermore, numerous studies have investigated how nano-silica impacts the properties of concrete (Ji, 2005; Madani et al., 2012; Said et al., 2012; Senff et al., 2009; Singh et al., 2013). As an example, Singh et al. (Singh et al., 2013) reported that the incorporation of nano-silica in cementitious materials enhances their strength and durability through the refinement of pore structure and acceleration of hydration processes. In addition to its nucleation and pore-filling effects, nano-silica exhibits pozzolanic reactivity owing to its chemical composition. This reactivity generates additional C-S-H, thereby facilitating the strength development of the cementitious composites (Singh et al., 2013). The improvement in the mechanical and durability performance in concrete resulted from the incorporation of nanoparticles has a great potential in reducing the expensive maintenance cost caused by the deterioration of freeze-thaw and deicers (Ali & Kharofa, 2021; Ferreira et al., 2023; Haleema Saleem, 2021). Nonetheless, nanomaterials are not as economical or abundantly available as other supplementary cementitious materials (e.g., fly ash, slag, etc.). More research should undertake to develop more economical synthesis methods and manufacturing technology on producing nanomaterials (Haleema Saleem, 2021) and assess the impact of nanomaterials from a life cycle perspective (Papanikolaou et al., 2019). Despite the considerable number of publications on the utilization of nano-TiO 2 and nano-silica to modify the properties of cementitious composites, there is a shortage of studies that compare the effects of using these nanomaterials on the durability of concrete cured at various temperatures. To partially fill this gap, the current paper presents the results of a series of experiments which were conducted to compare the impact of different nanoparticles (i.e., nano-TiO 2 and nano-silica) on the properties of concretes and how different curing temperatures impact the influence of nanoparticles on the performance of concrete. These properties include compressive and flexural strength, total pore volume, pore connectivity, water absorption, and scaling resistance. Two different curing